Step1: Cardboard cutout

To make this first u have to make a cardboard hollow cube box attach two screw on left side and two screw on right.

Step2: 

put a cardboard piece on it this structure will look like a drawer.

Then attach a servo on the back side with a tape or glue it.

Step3: Circuit Connection

I have used ultrasonic sensor for sensing, when we put our hand near to it, it senses the close distance and opens the drawer.

Schematic

As per the circuit connect a ultrasonic sensor and upload coding in the arduino .

Step4: Code

#include <Servo.h>
Servo my1;
int trigPin=11;
int echoPin= 9;
long duration, cm, inches;
void setup()
{
  my1.attach(8);
  Serial.begin(9600);
  pinMode(trigPin,OUTPUT);
  pinMode(echoPin,INPUT);
}
void loop()
{
  digitalWrite(trigPin,LOW);
  delayMicroseconds(1);
  digitalWrite(trigPin,HIGH);
  delayMicroseconds(1);
  digitalWrite(trigPin,LOW);
  pinMode(echoPin,INPUT);
  duration=pulseIn(echoPin,HIGH);
  cm=(duration/2)/29.1;
  inches=(duration/2)/74;
  Serial.print(inches);
  Serial.print("in");
  Serial.print(cm);
  Serial.print("cm");
  Serial.println();
  delay(1000);
  my1.write(0);
  if (cm<20){
    my1.write(90);
  }
  if (cm>20){
    my1.write(0);
  }
}  

Video

here is the implementation steps: